The Sitzmaschine, that is, the "machine for sitting," was originally designed by Hoffmann for his Purkersdorf Sanatorium in Vienna. The sanatorium was one of the first important commissions given to the Wiener Werkstätte, a collaborative founded in 1903 by Hoffmann and Koloman Moser espousing many of the English Arts and Crafts movement's tenets of good design and high-quality craftsmanship. It represents one of Hoffmann's earliest experiments in unifying a building and its furnishings as a total work of art.
The Sitzmaschine makes clear reference to an adjustable-back English Arts and Crafts chair known as the Morris chair, designed by Philip Webb around 1866. It also stands as an allegorical celebration of the machine. This armchair, with its exposed structure, demonstrates a rational simplification of forms suited to machine production. Yet, at the same time, the grid of squares piercing the rectangular back splat, the bentwood loops that form the armrests and legs, and the rows of knobs on the adjustable back illustrate the fusion of decorative and structural elements typical of the Wiener Werkstätte style. J. & J. Kohn produced and sold this chair in a number of versions, most of which had cushions on the seat and back, until at least 1916. The Kohn firm produced many designs by Hoffmann, forming one of the first successful alliances between a designer and industry in Vienna.
from The Museum of Modern Art, MoMA Highlights, New York: The Museum of Modern Art, revised 2004, originally published 1999, p. 56